The conclusion from these numbers is that image resolution does, in fact, correlate very well with pixel density while it doesn't correlate at all with sensor size.

You're depending very heavily on the theoretical here, though - as in theoretically, a 100MP point 'n shoot sensor will resolve far more than a 36MP FF sensor. This doesn't take diffraction, focus errors or lens imperfections into consideration. It's going to be harder to take advantage of all those MPs as the sensor area gets smaller, especially as you move up from base ISO, where noise is going to blur the smaller sensor even more.

Yes, I've yet to see a lens tested that provides the "theoretical" maximum resolution measured. I'm not sure what they're measuring, or how they're measuring it, but it doesn't seem to be on point (i.e., how the same lens performs on different formats). The DPR resolution tests indicate that "the relevant prime lens" was used (without specifying what that is in any given case), which doesn't compare the same lens on different format cameras (presumably) and therefore isn't really what the point of discussion here was.

...The images I posted - which were intended only as an illustration and not a test (as you descibed them) - bear this out: if you were right we wouldn't be discussing the fine detail of the two images because the D60 one would be far softer than the D700 one.